Abstract
After the first quasiperiodic eruption (QPE; GSN 069) was reported in 2019, four other sources have been identified as a QPE or a candidate. However, the physics behind QPEs is still ...unclear, although several models have been proposed. Pan et al. proposed an instability model for an accretion disk with magnetically driven outflows in the first QPE of GSN 069, which is able to reproduce both the light curve and the evolution of the spectra fairly well. In this work, we extend this model to all QPEs. We improve the calculations of the spectrum of the disk by introducing a hardening factor, which is caused by a deviation of opacity from a blackbody. We find that the light curves and evolution of the spectra of the four QPEs and candidates can all be well reproduced by our model calculations.
Ultrasound (US)‐triggered sonodynamic therapy (SDT), as a promising noninvasive therapeutic modality, has received ever‐increasing attention in recent years. Its specialized chemical agents, named ...sonosensitizers, are activated by low‐intensity US to produce lethal reactive oxygen species (ROS) for oncotherapy. Compared with phototherapeutic strategies, SDT provides many noteworthy opportunities and benefits, such as deeper penetration depth, absence of phototoxicity, and fewer side effects. Nevertheless, previous studies have also demonstrated its intrinsic limitations. Thanks to the facile engineering nature of nanotechnology, numerous novel nanoplatforms are being applied in this emerging field to tackle these intrinsic barriers and achieve continuous innovations. In particular, the combination of SDT with other treatment strategies has demonstrated a superior efficacy in improving anticancer activity relative to that of monotherapies alone. Therefore, it is necessary to summarize the nanomaterial‐assisted combinational sonodynamic cancer therapy applications. Herein, the design principles in achieving synergistic therapeutic effects based on nanomaterial engineering methods are highlighted. The ultimate goals are to stimulate the design of better‐quality combined sonodynamic treatment schemes and provide innovative ideas for the perspectives of SDT in promoting its future transformation to clinical application.
Sonodynamic therapy (SDT) is becoming a rising star on the horizon of nanomedicine and has received ever‐increasing attention in recent years. In particular, SDT‐involved combination therapy opens up new therapeutic possibilities and is developing into an exciting tide. An overview on nanomaterial‐assisted combinational sonodynamic cancer therapy is given, with the hope of advancing SDT toward the stage of clinical trials.
Abstract
Periodic outbursts are observed in several changing-look (CL) active galactic nuclei (AGNs). Sniegowska et al. suggested a model to explain the repeating CL in these AGNs, where the periodic ...outbursts are triggered in a narrow unstable zone between an inner advection-dominated accretion flow and outer thin disk. In this work, we intend to investigate the effects of large-scale magnetic fields on the limit cycle behaviors of CL AGNs. The winds driven by magnetic fields can significantly change the structure of thin disk by taking away the angular momentum and energy of the disk. It is found that the period of outburst in repeating CL AGNs can be substantially reduced by the magnetic fields. Conversely, if we keep the period unchanged, the outburst intensity can be raised by several times. These results can help to explain the observational properties of multiple CL AGNs. Besides the magnetic fields, the effects of transition radius
, the width of the transition zone Δ
R
, and the Shakura–Sunyaev parameter
α
are also explored in this work.
Abstract
GSN 069 is a recently discovered quasi-periodic eruption (QPE) source recurring about every 9 hr. The mechanism for the QPEs of GSN 069 is still unclear. In this work, a disk instability ...model is constructed to explain GSN 069 based on Pan et al. (PLC21), where the authors proposed a toy model for the repeating changing-look active galactic nuclei. We improve the work of PLC21 by including a nonzero viscous torque condition on the inner boundary of the disk and adopting a general form for the viscous stress torque in the Kerr metric. It is found that the 0.4–2 keV light curves, the light curves at different energy bands, and the phase-resolved X-ray spectrum of GSN 069 can all be qualitatively reproduced by our model. Furthermore, the profiles of light curves in QPEs can be significantly changed by the parameter
μ
in the viscous torque equation, which implies that our model may also be applied to other QPEs.
Periodontitis is an infection-driven inflammatory disease, which is characterized by gingival inflammation and bone loss. Periodontitis is associated with various systemic diseases, including ...cardiovascular, respiratory, musculoskeletal, and reproductive system related abnormalities. Recent theory attributes the pathogenesis of periodontitis to oral microbial dysbiosis, in which Porphyromonas gingivalis acts as a critical agent by disrupting host immune homeostasis. Lipopolysaccharide, proteases, fimbriae, and some other virulence factors are among the strategies exploited by P. gingivalis to promote the bacterial colonization and facilitate the outgrowth of the surrounding microbial community. Virulence factors promote the coaggregation of P. gingivalis with other bacteria and the formation of dental biofilm. These virulence factors also modulate a variety of host immune components and subvert the immune response to evade bacterial clearance or induce an inflammatory environment. In this chapter, our focus is to discuss the virulence factors of periodontal pathogens, especially P. gingivalis, and their roles in regulating immune responses during periodontitis progression.
Alzheimer's disease (AD) is the most prevalent neurodegenerative disease causing dementia and poses significant health risks to middle-aged and elderly people. Brain magnetic resonance imaging (MRI) ...is the most widely used diagnostic method for AD. However, it is challenging to collect sufficient brain imaging data with high-quality annotations. Weakly supervised learning (WSL) is a machine learning technique aimed at learning effective feature representation from limited or low-quality annotations. In this paper, we propose a WSL-based deep learning (DL) framework (ADGNET) consisting of a backbone network with an attention mechanism and a task network for simultaneous image classification and image reconstruction to identify and classify AD using limited annotations. The ADGNET achieves excellent performance based on six evaluation metrics (Kappa, sensitivity, specificity, precision, accuracy, F1-score) on two brain MRI datasets (2D MRI and 3D MRI data) using fine-tuning with only 20% of the labels from both datasets. The ADGNET has an F1-score of 99.61% and sensitivity is 99.69%, outperforming two state-of-the-art models (ResNext WSL and SimCLR). The proposed method represents a potential WSL-based computer-aided diagnosis method for AD in clinical practice.
ABSTRACT
In this work, a nearby luminous active galactic nucleus (AGN) sample is selected from Hubble Space Telescope(HST), where only sources with both X-ray emission observed by Chandra/XMM–Newton ...and radio flux detected by Very Large Array (VLA)/Very Long Baseline Array (VLBA)/very long baseline interferometry (VLBI)/Multi-Element Radio Linked Interferometer Network (MERLIN) are adopted to keep high precision. Finally, we get a sample of 30 luminous AGNs, which consists of 11 radio-loud AGNs (RLAGN) and 19 radio-quiet AGNs (RQAGN). It is found that the relationship between RUV and αox, which was first reported by Li & Xie in low-luminosity AGNs (LLAGN), and other relationships are all absent in RLAGN, probably due to the complex physical process therein. Our results indicate that the X-ray emission from jet should play an important role in RLAGN and further support the transition of accretion mode between LLAGN and RLAGN. On the other hand, the traditional relationships in RQAGN, such as αox and λ, Γ and λ, are found to be well consistent with previous works.
Chitooligosaccharide (COS), which is acknowledged for possessing multiple functions, is a kind of low-molecular-weight polymer prepared by degrading chitosan via enzymatic, chemical methods, etc. COS ...has comprehensive applications in various fields including food, agriculture, pharmacy, clinical therapy, and environmental industries. Besides having excellent properties such as biodegradability, biocompatibility, adsorptive abilities and non-toxicity like chitin and chitosan, COS has better solubility. In addition, COS has strong biological functions including anti-inflammatory, antitumor, immunomodulatory, neuroprotective effects, etc. The present paper has summarized the preparation methods, analytical techniques and biological functions to provide an overall understanding of the application of COS.
Aims.
Whether X-ray emission in radio-loud (RL) active galactic nuclei (AGNs) originates from disk coronae or jets is still under debate. For example, the positive relationships in radio-quiet AGNs ...(such as the optical to X-ray spectral index
α
OX
and Eddington ration
λ
O
as well as the X-ray photon index Γ and
λ
O
) are not detected in RLAGNs. We intend to further investigate this issue in this work.
Methods.
A sample of 27 luminous sources (including 16 quasars and 11 high-excitation radio galaxies) was selected from the 3CRR catalog to reinvestigate the origin of X-ray emission in RLAGNs, where the X-ray and mid-infrared fluxes are observed by
Chandra/XMM-Newton
and
Spitzer
, respectively.
Results.
It is found for the first time that there is a significant relationship between the mid-infrared to X-ray spectral index
α
IX
and
λ
IR
for whole sample, while there is no relationship between
α
OX
and
λ
O
in quasars. There are strong positive relationships between both
L
R
−
L
X
and
L
UV
−
L
X
panels, which can be well fitted by the disk-corona model. However, there is no significant relationship between Γ and
λ
IR
. The possible reason is related to the effects of the large-scale magnetic field in RLAGNs.
Conclusions.
We suggest that the X-ray emission in high-excitation RLAGNs originates from a disk-corona system.